Nonlinearity with Disorder


Book Description

In the past three decades there has been enormous progress in identifying the essential role that nonlinearity plays in physical systems, including supporting soliton-like solutions and self-trapped sxcitations such as polarons. during the same period, similarly impressive progress has occurred in understanding the effects of disorder in linear quantum problems, especially regarding Anderson localization arising from impurities, random spatial structures, stochastic applied fields, and so forth. These striking consequences of disorder, noise and nonlinearity frequently occur together in physical systems. Yet there have been only limited attempts to develop systematic techniques which can include all of these ingredients, which may reinforce, complement or frustrate each other. This book contains a range of articles which provide important steps toward the goal of systematic understanding and classification of phenomenology. Experts from Australia, Europe, Japan, USA, and the USSR describe both mathematical and numerical techniques - especially from soliton and statistical physics disciplines - and applicaations to a number of important physical systems and devices, including optical and electronic transmission lines, liquid crystals, biophysics and magnetism.




Nonlinearity and Disorder: Theory and Applications


Book Description

Proceedings of the NATO Advanced Research Workshop, Tashkent, Uzbekistan, 2-6 October 2001







Future Directions of Nonlinear Dynamics in Physical and Biological Systems


Book Description

Early in 1990 a scientific committee was formed for the purpose of organizing a high-level scientific meeting on Future Directions of Nonlinear Dynamics in Physical and Biological Systems, in honor of Alwyn Scott's 60th birthday (December 25, 1991). As preparations for the meeting proceeded, they were met with an unusually broad-scale and high level of enthusiasm on the part of the international nonlinear science community, resulting in a participation by 168 scientists from 23 different countries in the conference, which was held July 23 to August 11992 at the Laboratory of Applied Mathematical Physics and the Center for Modelling, Nonlinear Dynamics and Irreversible Thermodynamics (MIDIT) of the Technical University of Denmark. During the meeting about 50 lectures and 100 posters were presented in 9 working days. The contributions to this present volume have been grouped into the following chapters: 1. Integrability, Solitons, and Coherent Structures 2. Nonlinear Evolution Equations and Diffusive Systems 3. Chaotic and Stochastic Dynamics 4. Classical and Quantum Lattices and Fields 5. Superconductivity and Superconducting Devices 6. Nonlinear Optics 7. Davydov Solitons and Biomolecular Dynamics 8. Biological Systems and Neurophysics. AI Scott has made early and fundamental contributions to many of these different areas of nonlinear science. They form an important subset of the total number of the papers and posters presented at the meeting. Other papers from the meeting are being published in a special issue of Physica D Nonlinear Phenomena.




Nonlinearity in Condensed Matter


Book Description

The Sixth Annual Conference of the Center for Nonlinear Studies at the Los Alamos National Laboratory was held May 5-9, 1986, on the topic "Nonlinearity in Condensed Matter: Lessons from the Past and Prospects for the Future. " As conference organizers, we felt that the study of non linear phenomena in condensed matter had matured to the point where it made sense to take stock of the numerous lessons to be learned from a variety of contexts where nonlinearity plays a fundamental role and to evaluate the prospects for the growth of this general discipline. The successful 1978 Oxford Symposium on nonlinear (soliton) struc ture and dynamics in condensed matter (Springer Ser. Solid-State Sci. , Vol. 8) was held at a time when the ubiquity of solitons was just begin ning to be appreciated by the condensed matter community; in subsequent years the soliton paradigm has provided a rather useful framework for in vestigating a large number of phenomena, particularly in low-dimensional systems. Nevertheless, we felt that the importance of nonlinearity in wider arenas than "solitonics" merited a significant expansion in the scope of the conference over that of the 1978 symposium. Indeed, many of the lessons are quite general and their potential for cross-fertilization of otherwise poorly connected disciplines was certainly one of the prime motivations for this conference. Thus, while these proceedings contain many contribu tions pertaining to soliton behavior in different contexts, the reader will find much more as well, particularly in the later chapters.










Nonlinear Optics and Laser Emission through Random Media


Book Description

Disorder is everywhere, inherently present in nature, and is commonly believed to be a synonymous with disturbance. As a consequence, the methodical and customary study of the dynamics of the electromagnetic field, both in the linear and nonlinear optical regimes, leans to rule out it from the treatment. On the other hand, nonlinearity enriches the physical disciplines and brings them closer to reality with respect to the linear approximation. Nonlinearity allows to stimulate a wide and rich ensemble of optical responses that beautifies the role of matter in the active processes with electromagnetic fields. Independently of each other, both of these mechanisms foster localization of light. What happens when light enlightens their synergistic interaction? When pushed together, light, disorder and nonlinearity make new and intriguing phenomena emerge. This text provides a comprehensive investigation of the role of disorder in the nonlinear optical propagation both in transparent media and lasers. Eventually, disorder promotes and enhances complex nonlinear dynamics opening new perspectives in applied research driven by the processes of localization of the electromagnetic field. The first experimental study of laser emission in granular media unveils how randomness magnifies and largely affect laser-matter interactions. Viola Folli in her research work touches and deepens the leading milestones of the new science named Complex Photonics.




Complexity and Nonlinearity in Cardiovascular Signals


Book Description

This book reports on the latest advances in complex and nonlinear cardiovascular physiology aimed at obtaining reliable, effective markers for the assessment of heartbeat, respiratory, and blood pressure dynamics. The chapters describe in detail methods that have been previously defined in theoretical physics such as entropy, multifractal spectra, and Lyapunov exponents, contextualized within physiological dynamics of cardiovascular control, including autonomic nervous system activity. Additionally, the book discusses several application scenarios of these methods. The text critically reviews the current state-of-the-art research in the field that has led to the description of dedicated experimental protocols and ad-hoc models of complex physiology. This text is ideal for biomedical engineers, physiologists, and neuroscientists. This book also: Expertly reviews cutting-edge research, such as recent advances in measuring complexity, nonlinearity, and information-theoretic concepts applied to coupled dynamical systems Comprehensively describes applications of analytic technique to clinical scenarios such as heart failure, depression and mental disorders, atrial fibrillation, acute brain lesions, and more Broadens readers' understanding of cardiovascular signals, heart rate complexity, heart rate variability, and nonlinear analysis




Nonlinearity in Living Systems: Theoretical and Practical Perspectives on Metrics of Physiological Signal Complexity


Book Description

The biological basis of physiological signals is incredibly complex. While many types of research certainly appreciate molecular, cellular and systems approach to unravel overall biological complexity, in the recent decades the interest for mathematical and computational characterization of structural and functional basis underlying biological phenomena gain wide popularity among scientists. Nowadays, we witnessed wide range applications of nonlinear quantitative analysis that produced measures such as fractal dimension, power-law scaling, Hurst exponent, Lyapunov exponent, approximate entropy, sample entropy, Lempel–Ziv complexity, as well as other metrics for predictions of onset and progression of many pathological conditions, especially in the central nervous systems (CNS). In this Research Topic, we seek to bring together the recent practical and theoretical advances in the development and application of nonlinear methods or narrower fractal-based methods for characterizing the complex physiological systems at multiple levels of the organization. We will discuss the use of various complexity measures and appropriate parameters for characterizing the variety of physiological signals up to the systems level. There are multiple aims in this topic. The recent advancement in the application of nonlinear methods for both normal and pathological physiological conditions is the first. The second aim is to emphasize the more recent successful attempt to apply these methods across animal species. Finally, a comprehensive understanding of advantages and disadvantages of each method, especially between its mathematical assumptions and real-world applicability, can help to find out what is at stake regarding the above aims and to direct us toward the more fruitful application of nonlinear measures and statistics in physiology and biology in general.